I've got a full suspension XC/AM 29er mountain bike (Gary Fisher Hi-Fi Pro). I'm running a size small frame with an 80mm stem with about 7 degree rise. Bike seems like a good fit for me. I do run the seat a touch lower than optimal for more room to move on sketchy sections (no dropper post) but still not so much that my legs scream on flats and climbs.
However on a lot of climbs, even ones that are not super steep, my front wheel seems to pop up quite a bit. This makes me have to foot down unexpectedly when the climbs are rooty or rocky. I try to get as close to the bars as possible when I'm digging hard, but I feel like something might be better done with bike fit than bike english.
What should I try to set up the bike to avoid this? I switched from a slightly longer 90mm stem due to the feeling I was going to OTB on sketchy terrain, so I don't want to play with lengthening the stem much.
Things I considered:
What's going to be the most effective way to change the setup to avoid or reduce the lifting effect?